Those attacks included Trump doubling down on his comparison of what he has called Carson's incurable "pathological temper" to child molesters, while at the same time questioning Carson's account of his violent childhood incidents. This all occurred during a 95-minute speech in Fort Dodge, Iowa.

"How stupid are the people of Iowa? How stupid are the people of the country to believe this crap?" Trump asked his supporters of Carson's stories.

He was referring to Carson's memoir, "Gifted Hands," in which the retired neurosurgeon described a series of five-decade-old attacks by him against his family and friends.

Trump has latched onto a line from the book in which Carson wrote, "I had what I only can label a pathological temper — a disease — and this sickness controlled me, making me totally irrational."

Carson said he eventually turned his life around by excelling in school and dispelling his anger. Today, the world-renowned doctor is known for often speaking barely above a whisper and refusing to criticize his rivals on the campaign trail.

"If you're a child molester — a sick puppy, you're a child molester — there's no cure for that," Trump said Thursday. "There's only one cure. We don't want to talk about that cure. That's the ultimate cure."

Trump pointed to three of Carson's claimed violent teenage incidents in particular: attempting to attack his mother with a hammer, hitting someone with a padlock, and trying to stab a friend. But at the same time, Trump expressed disbelief at Carson's claims.

"Give me a break, the knife broke," he said, reenacting one of Carson's stories. "He took the knife, he went like this! And he plunged it into the belt! And amazingly, the belt stayed totally flat and the knife broke."

And Trump discounted how Carson could have had an epiphany had he truly been as violent as his book described.

"He goes into the bathroom for a couple hours, and comes out, and now he's religious," Trump said. "And the people of Iowa believe him. Give me a break. Give me a break. It doesn't happen that way. It doesn't happen that way."

"Dr. Carson [was] 14 years old at the time, it was a half century ago," Williams told the network. "Mr. Trump speaks of this as if it happened within the last year. I mean, are you kidding me? It's so sad watching and listening to him."